A nurse recommended this 100% DEET product from the Amazon online store. It really is the best mosquito repellent I've used. I went travelling around Sri Lanka, staying in the hill country, mountains and beach resorts, not all places had mosquito nets, every night before venturing out, I'd smother myself in it and i only got bit once (truth!).
The product is quite oily, looks like you've applied baby oil, but rubs in, a little goes a long way (although I hosed myself down with it, just to be safe!) I kept touching my arms/legs/face (out of habit throughout the night) and found the product easily transfers to fingers, not a great taste when nibbling bread/snacks (perfect reason to wash your hands more!). Also it seemed to melt my nail varnish off and the make dyes come off my shoes and watch (cheap material to blame though!). Really recommend this product!